1. Field of the Invention
The present invention relates to an organic electro-luminescence display device, and more particularly, to a dual panel-type organic electro-luminescence display device capable of achieving reliability and a method for manufacturing the same.
2. Description of the Related Art
An organic electro-luminescence display device uses a phenomenon that carriers such as electrons and holes create electron-hole pairs or carriers are excited to a higher energy state and then fall down to a ground state, which is a stable state, inside a semiconductor to generate light.
Since the organic electro-luminescence display device is a self-luminous type display device and thus does not require a backlight unit as in a liquid crystal display (LCD) device, it can be manufactured in lightweight and a slim profile. Also, the organic electro-luminescence display device has advantages of low voltage driving, a high light-emitting efficiency, a wide viewing angle, and a fast response time, and is advantageous in realizing a high quality moving image.
Particularly, unlike an LCD device or a plasma display panel (PDP), deposition and encapsulation equipment occupy most of the manufacturing process of the organic electro-luminescence display device, thus the manufacturing process is very simple.
Also, in the case where the organic electro-luminescence display device is driven using an active matrix in which each pixel has a thin film transistors (TFT), which is a switching device, same brightness is achieved even when a low current is applied, so that low power consumption, high definition, and a large size can be realized.
FIG. 1 is a schematic cross-sectional view of an organic electro-luminescence display device according to a related art. Referring to FIG. 1, a TFT Tr is formed on the substrate 10. The TFT includes a gate electrode 15, an active layer 25, and source/drain electrodes 27a and 27b. 
The substrate 10 includes a passivation layer 20 having a contact hole exposing a portion of the drain electrode 27b. 
A first electrode 30 is formed on the passivation layer 20, and electrically connected to the drain electrode 27b via the contact hole.
An insulating layer 40 where a pixel region is defined is located on the passivation layer 20. An organic luminescence layer 50 is disposed on a portion of the first electrode 30 that corresponds to the pixel region. A second electrode 60, which is a common electrode, is disposed on the organic luminescence layer 50.
Here, the first and second electrodes 30 and 60 apply a forward current on the organic luminescence layer 50 to allow the organic luminescence layer 50 to emit light.
After that, after sealant 70 is coated on an outer edge of the substrate 10 in order to protect the organic light-emitting diode device E formed on the substrate 10 from external humidity and oxygen, an encapsulating substrate 80 facing the organic light-emitting diode device E is attached, so that the organic electro-luminescence display device is manufactured. The organic electro-luminescence display device is classified into a bottom-emission type organic electro-luminescence display device and a top-emission type organic electro-luminescence display device depending on an emitting direction of an image.
The bottom-emission type organic electro-luminescence display device has a disadvantage that it is difficult to apply the display device to a high resolution product due to limitations in an aperture ratio.
On the other hand, the top-emission type organic electro-luminescence display device has an advantage in an aspect of a product growth in that designing a TFT is easy and an aperture ratio can be improved.
However, since a cathode is generally located on an organic light-emitting layer in a top-emission type organic electro-luminescence display device according to a related art, a material of an electrode is difficult to select. Accordingly, transmittance is limited and a light efficiency reduces.
Also, in the top-emission type organic electro-luminescence display device according to a related art, a pad portion for receiving a signal from an outside is exposed to the outside. The pad portion is formed of metal and easily corroded by external oxygen and moisture.
The corrosion of the pad portion increases contact resistance between metal of the pad portion and contact metal of an external circuit unit to generate a dark pixel. Furthermore, the corrosion of the pad portion may reduce reliability of the organic electro-luminescence display device.